Kinematic Calibration of Linear-Actuated Parallel Mechanisms from Leg Observation

International audienceIn this article, an original algorithm is proposed to achieve the kinematic calibration of parallel mechanisms with linear actuators on the base, using vision as an exteroceptive sensor to perform measurements on the legs of the mechanism. The calibration can be performed without adding proprioceptive sensors or re- stricting the mechanism’s workspace during the calibration process. The algorithm is implemented for the calibration of the I4 parallel mechanism with experimental results

A Study on Dexterous Grasps via Parallel Manipulation Analogy

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On Vision-based Kinematic Calibration of a Stewart-Gough Platform

International audienceIn this article, we propose a vision-based kinematic calibration algorithm for Stewart-Gough parallel structures. Information on the position and orientation of the mechanism legs is extracted from the observation of these kinematic elements with a standard camera. No workspace limitation, nor installation of additional proprioceptive sensors are required. The algorithm is composed of two steps: the first one enables us to calibrate the position of the joint centers linked to the base and possibly evaluate the presence of joint clearances. The kinematic parameters associated to the moving elements of the platform are calibrated in a second step. The algorithm is first detailed, then an experimental evaluation of the measurement noise is performed, before giving simulation results. The algorithm performance is then discussed

On vision-based kinematic calibration of n-leg parallel mechanisms

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Etalonnage géométrique de mécanismes parallèles par vision

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Identification géométrique de mécanismes parallèles par vision

National audienceIn this article we present the use of a vision-based measuring device for the kinematic calibration of parallel mechanisms. Vision enables one to perform simultaneously position and orientation measurements of the mechanism end-effector. A vision-based measuring device therefore allows one to use the inverse kinematic model method, particularly efficient in simulation. In this article the parameter identifiability conditions are analyzed. The kinematic calibration of a H4 parallel mechanism is then presented, with parameter identifiability study. Experimental results are finally presented with an influence analysis of the identification model.Dans cet article nous présentons l'utilisation d'un outil de métrologie par vision pour l'identification géométrique de mécanismes parallèles. La vision permet d'obtenir si-multanément la position et l'orientation de l'effecteur du mécanisme. Un outil de métrologie par vision permet donc l'utilisation de la méthode du modèle géométrique inverse, particulièrement efficace en simulation. Dans cet article les conditions d'identifiabilité des paramètres par vision sont analysées. L'identification d'un mécanisme parallèle H4 est alors présentée, en analysant l'identifiabilité de deux modèles. Des résultats expérimentaux montrant la nette amélioration de la précision du mécanisme et l'influence du choix du modèle sont enfin décrits, avant de conclure sur l'identification d'une telle classe de mécanismes

Redundancy-based optimization approach to optimize robotic cell behaviour: application to robotic machining

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Modelling and simulation of an harvester head mechanism

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